What is Peak?

Peak

Peak

Basic Concepts

The term “Peak” refers to the maximum amplitude of a signal, representing the highest value in a waveform. The peak indicates the instantaneous size of the signal and does not account for variations over time or average values. Therefore, the peak value can differ significantly from the actual perceived volume.

Applications

Max output level
Max input level


In audio, the Peak is especially used to indicate the maximum output level or maximum input level of an acoustic signal. The peak value is commonly expressed in units such as dBu or dBFS and plays a crucial role in various domains like music production, live performances, and sound system design.


True Peak? Sample Peak?

True peak

To accurately measure the peak value in digital formats, one must consider the sampling rate. A lower sampling rate may result in less accurate peak detection. It’s important to note that the peak value represents the instantaneous maximum amplitude and is a different concept from average or RMS values.

In digital audio, even if sample data are below the peak value, the actual analog waveform can exceed this peak value when played back. This is due to the characteristics of the digital signal’s quantization stage and the D/A converter’s operation. Therefore, the True Peak value is used to infer the maximum amplitude when converting the sample data into an actual analog waveform.

[Refer to the dBTP document]